Semiconductor device

ABSTRACT

There is provided a semiconductor device including a picture display function and a picture capturing function on the same substrate. The semiconductor device includes a pixel matrix, an image sensor, and a peripheral circuit for driving those, which are provided on the same substrate. Moreover, in the semiconductor device, the structure/manufacturing process of the image sensor is made coincident with the structure/manufacturing process of the pixel matrix and the peripheral driver circuit, so that the semiconductor device can be manufactured at low cost.

This application is a divisional of U.S. application Ser. No.09/309,966, filed on May 11, 1999, now U.S. Pat. No. 6,236,063.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a semiconductor device having both animage sensor function and a picture display function. More particularly,the present invention relates to an active matrix type semiconductordevice constituted by a plurality of thin film transistors (TFTs)arranged in a matrix form.

2. Description of the Related Art

In recent years, a technique for a TFT using polycrystal silicon(polysilicon TFT) has been diligently studied. As a result, it becomespossible to form a driver circuit including a shift register circuit andthe like by use of the polysilicon TFT, and an active matrix type liquidcrystal panel in which a pixel region and a peripheral driver circuitfor driving the pixel region are integrated on the same substrate hasbeen put to practical use. Thus, a liquid crystal panel is miniaturizedand its weight is lessened, and the liquid crystal panel is used as adisplay portion of various kinds of information equipment and portableequipment, such as a personal computer, a video camera, and a digitalcamera.

Recently, a pocket-sized small portable information processing terminaldevice (mobile computer) which is superior to a note-sized personalcomputer in portability and is inexpensive, becomes popular, and anactive matrix type liquid crystal panel is used as its display portion.In such an information processing terminal device, data can be inputtedfrom the display portion in a touch-pen system. However, it is necessaryto connect it with a peripheral equipment for reading a picture, such asa scanner or a digital camera, in order to input character/drawinginformation on a sheet or image information. Thus, the portability ofthe information processing terminal device is vitiated. Moreover, aneconomical burden is imposed on users.

The active matrix type liquid crystal display device is also used for adisplay portion of a TV meeting system, a TV telephone, a terminal forthe Internet, and the like. Although such a system or terminal includesa camera (CCD camera) for taking a picture of a dialogist or a user, adisplay portion and a reading portion (sensor portion) are separatelymanufactured, and are made into a module. Thus, the manufacturing costis high.

SUMMARY OF THE INVENTION

The present invention has been made in view of the above problems, andtherefore has an object of the invention to provide a semiconductordevice including a pixel matrix, an image sensor, and a peripheralcircuit for driving those, that is, a novel semiconductor device havingboth an image pickup function and a display function and madeintelligent.

Another object of the present invention is to manufacture a novelintelligent semiconductor device at low cost by making thestructure/manufacturing process of an image sensor coincident with thestructure/manufacturing process of a pixel matrix and a peripheraldriver circuit.

In order to solve the foregoing problems, the present invention adoptssuch a structure that a display semiconductor device for displaying apicture and a light receiving semiconductor device for capturing apicture are provided on the same substrate. The structure of the presentinvention is as follow.

According to an aspect of the present invention, a semiconductor devicecomprises an active matrix substrate including a plurality of pixelsarranged in a matrix form and a plurality of sensor portions arranged ina matrix form; and a backlight; wherein each of the sensor portionscomprises a photoelectric conversion element, and the backlight is to beused as a light source when an external picture is read. The aboveobjects can be achieved by this.

According to another aspect of the present invention, a semiconductordevice comprises an active matrix substrate including a plurality ofpixels arranged in a matrix form and a plurality of sensor portionsarranged in a matrix form; and a backlight; wherein each of the sensorportions includes a pixel reflecting electrode, the pixel reflectingelectrode includes a plurality of window for allowing light to pass,each of the sensor portions comprises a photoelectric conversionelement, and the backlight is to be used as a light source when anexternal picture is read. The above objects can be achieved by this.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings:

FIG. 1 is a circuit diagram of a semiconductor device of an embodimentof the present invention;

FIG. 2 is an analytic view of a semiconductor device of the presentinvention;

FIG. 3 is an analytic view of a semiconductor device of the presentinvention;

FIG. 4 is a sectional view of an active matrix substrate of asemiconductor device of an embodiment of the present invention;

FIGS. 5A to 5D are views showing a manufacturing method of asemiconductor device of the present invention;

FIGS. 6A to 6C are views showing the manufacturing method of thesemiconductor device of the present invention; and

FIG. 7 is a sectional view of an active matrix substrate of asemiconductor device of an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

First, a typical embodiment of a semiconductor device of the presentinvention will be described below. However, the present invention is notlimited to the embodiment described below.

Reference will be made to FIG. 1. FIG. 1 shows an example of a circuitstructure of a semiconductor device of the present invention. Forconvenience of explanation, FIG. 1 shows the circuit structure of thesemiconductor device with 2×2 (vertical×horizontal) pixels. Peripheralcircuits are simply shown with blocks.

Reference numeral 101 denotes a pixel TFT, 102 denotes a liquid crystal,103 denotes an auxiliary capacitor. Various Known liquid crystalmaterials such as twisted nematic liquid crystal, polymer dispersionliquid crystal, ferroelectric liquid crystal, anti-ferroelectric liquidcrystal, thresholdless antiferroelectric liquid crystal (TLAFLC) or amixture of ferroelectric and anti*-ferroelectric liquid crystals may beuse in the liquid crystal display of thin example.

Reference numeral 104 denotes a sensor TFT, 105 denotes a photodiode PD,106 denotes an auxiliary capacitor, 107 denotes a signal amplifying TFT,108 denotes a reset TFT, and 109 and 110 denote analog switches. Thecircuit constituted by these elements 101 to 108 will be called a matrixcircuit. Further, the portion constituted by the elements 101 and 103will be called a pixel region A, and the portion constituted by theelements 104, 105, 106, 107, and 108 will be called a sensor portion B.Reference numeral 111 denotes a sensor output signal line, and 112denotes a picture input signal line. Reference numerals 113 and 114denote fixed potential lines. Reference numeral 115 denotes a pixelsource signal line side driver circuit, 116 denotes a pixel gate signalline side driver circuit, 117 denotes a sensor horizontal drivercircuit, and 118 denotes a sensor vertical driver circuit.

In the semiconductor device-of the present invention, in the case wherea picture is displayed, a picture signal (gradation voltage) inputtedfrom the picture input signal line is supplied to the pixel TFT throughthe pixel source signal line side driver circuit 115 and the pixel gatesignal line side driver circuit 116, and the liquid crystal sandwichedbetween a pixel electrode connected to the pixel TFT and an oppositeelectrode is driven, so that the picture can be displayed. In FIG. 1,although an analog driver circuit is shown for the pixel source signalline side driver circuit 115 and the pixel gate signal line side drivercircuit 116, the invention is not limited to analog system. That is, adigital conversion circuit incorporating a D/A conversion circuit toprocess a digital image signal may be used.

Moreover, in the semiconductor device of the present invention, anincident external image (light signal) is read by the photodiode PD andis converted into an electric signal, and the image is captured by thesensor horizontal driver circuit 117 and the sensor vertical drivercircuit 118. This image signal is captured in other peripheral circuits(memory, CPU, etc.) through the sensor output signal line 111.

FIGS. 2 and 3 show the state in which the semiconductor device of thepresent invention is decomposed into structural parts. In FIGS. 2 and 3,for convenience of explanation, an interval between the respectivestructural parts is enlarged and is shown. Further, in FIGS. 2 and 3,the semiconductor device of the present invention is used in normallywhite display (white display when voltage is not applied) of a TN(twisted nematic) mode. A liquid crystal display method of another modesuch as an STN mode or an ECB mode may be used. Normally black display(black display when voltage is not applied) may be used.

Reference will be made to FIG. 2. FIG. 2 shows the state of the casewhere the semiconductor device of the present invention is used in apicture display mode. Reference numeral 201 denotes an active matrixsubstrate including a matrix circuit 201-1, a pixel source signal lineside driver circuit 201-2, a pixel gate signal line side driver circuit201-3, a sensor horizontal driver circuit 210-4, a sensor verticaldriver circuit 201-5, and another peripheral circuit 201-6, which havebeen described in FIG. 1. Although an oriented film and the like areformed over the active matrix substrate, they are not shown here.Reference numeral 202 denotes a liquid crystal. Reference numeral 203denotes an opposite substrate, which includes a transparent electrodeand an oriented film (both not shown). Reference numerals 204 and 205denote polarizing plates, which are arranged in crossed Nicols eachother. Reference numeral 206 denotes a backlight. Reference numeral 207schematically denotes a user (user's eye), and indicates the state wherethe user observes the semiconductor device of the present invention fromthe above. For the purpose of preventing the polarizing plate from beingdamaged or being covered with dust, a glass substrate, a plasticsubstrate, or the like (not shown) is provided on the upper portion ofthe upper polarizing plate 204.

In the case where the semiconductor device of the present invention isused as the picture display mode, a gradation voltage is supplied to thepixel TFT on the basis of a supplied image signal (it may be a signalstored in a built-in memory or the like, or may be a signal suppliedfrom the outside), and the liquid crystal 202 is driven. Color displaycan also be made by using a color filter.

Next, reference will be made to FIG. 3. FIG. 3 shows the state of thecase where the semiconductor device of the present invention is used ina picture reading mode. With respect to the structural partsconstituting the semiconductor device, reference may be made to theexplanation of FIG. 2. Reference numeral 301 denotes a picture readobject, for example, a business card or a photograph. In FIG. 3,although the picture read object is shown to be separate from thepolarizing plate (or not-shown glass substrate or plastic substrate), itis preferable to make arrangement so that the object is in close contactwith the plate.

In the case where the semiconductor device of the present invention isused in the picture reading mode, voltage is not applied to the pixelTFT so that the display with all the pixels is made white display. Bydoing so, light is reflected to the surface of the picture read object301. The light irradiated to the surface of the picture read object isreflected on the surface of the picture read object 301. At this time,the reflected light includes picture information of the picture readobject 301. This reflected light passes through the glass substrate (notshown), the polarizing plate, the opposite substrate, and the liquidcrystal, and is detected by the photodiode PD in the sensor portion B ofthe active matrix circuit of the active matrix substrate, so thatconversion into an electric signal is carried out. The pictureinformation converted into the electric signal is taken from the sensoroutput signal line as described above, and is stored in a memory (it maybe formed on the same substrate or may be disposed at the outside). Inthis way, the picture of the picture read object 301 is captured.

Although the explanation has been made on the case where a business cardor a photograph is brought into close contact with the semiconductordevice of the present invention, the picture of a scene or a person istaken with a digital camera, and the picture may be captured.

When the picture converted into the electric signal by the sensorportion B is displayed by the pixel region A, it can be displayed almostin real time. The pixel region A may be structured so that data from theoutside of the semiconductor device can be displayed.

Next, a sectional structure of the active matrix substrate of thesemiconductor device of the present invention will be described.Reference will be made to FIG. 4. The active matrix substrate of thesemiconductor device of the present invention includes, as shown in FIG.2, the pixel region A and the sensor portion B in one pixel. FIG. 4shows a pixel TFT and a sensor TFT. A light shielding film 404 isdisposed on a substrate 400 to make such a structure that the pixel TFTis protected against light incident from the back surface of thesubstrate. As shown in the drawing, such a structure may be adopted thata light shielding film 405 is disposed for the sensor TFT at the side ofthe sensor portion B. Moreover, a light shielding film (not shown) maybe disposed also for a reset TFT or signal amplifying TFT (both notshown) of the sensor portion B. These light shielding films may bedirectly disposed on the back surface of the substrate 400.

After an underlayer film 401 is formed on the light shielding films 404and 405, the pixel TFT of the display portion A, the sensor TFT of thesensor portion B, the signal amplifying TFT, the reset TFT, and TFTsconstituting the driver circuit and peripheral circuit are manufacturedat the same time. Here, the back surface of the substrate 400 indicatesa substrate surface on which TFTs are not formed. The structure of theTFT may be a top gate type or a bottom gate type. FIG. 4 shows the caseof the top gate type TFT as an example.

A lower electrode 420 connected to an electrode 419 of the sensor TFT isprovided. This lower electrode 420 serves as a lower electrode of aphotodiode (photoelectric conversion element), and is formed in thepixel region other than the upper portion of the pixel TFT. Aphotoelectric conversion layer 421 is disposed on the lower electrode420, and further, an upper electrode 422 is disposed thereon, so thatthe photodiode is completed. A transparent electrode is used for theupper electrode 422.

On the other hand, the pixel TFT of the pixel region is provided with apixel transparent electrode 424 connected to the electrode 416. Thispixel transparent electrode may be structured to cover the sensorportion B and a wiring line. In the case of the structure to cover thewiring line, a capacitor is formed with an insulating film, which existsbetween the wiring line and the pixel transparent electrode, as adielectric.

A manufacturing process of the semiconductor device of the presentinvention is substantially the same as manufacturing steps of aconventional display device except that manufacturing steps of thephotodiode is added. Thus, since a conventional manufacturing processcan be used, the semiconductor device can be manufactured easily and atlow cost. Moreover, in the semiconductor device manufactured by thepresent invention, its shape and size are not changed from aconventional panel even if the sensor function is incorporated. Thus,the semiconductor device can be miniaturized and can be madelightweight.

Next, although preferred embodiments of the present invention will bedescribed in more detail, the present invention is not limited to thefollowing embodiments.

(Embodiment 1)

In this embodiment, an example of a manufacturing method of asemiconductor device of the present invention will be described withreference to FIGS. 5A to 5D and FIGS. 6A to 6C. In the followingexplanation, although a pixel TFT and a sensor TFT will be typicallyshown, a reset TFT, a signal amplifying TFT, an analog switch, a drivercircuit, and a P-channel TFT and an N-channel TFT constituting aperipheral circuit can also be manufactured at the same time.

Reference will be made to FIGS. 5A to 5D. First, an underlayer film 401is formed on the whole surface of a substrate having transparentproperties 400. As the substrate 400, a glass substrate or quartzsubstrate having transparent properties can be used. As the underlayerfilm 401, a silicon oxide film with a thickness of 150 nm was formed bya plasma CVD method. In this embodiment, prior to the step of formingthe underlayer film, there were provided a light shielding film 404 forprotecting the pixel TFT against light from the back surface of thesubstrate 400, and a light shielding film 405 for protecting the sensorTFT against light from the back surface.

Next, an amorphous silicon film with a thickness of 30 to 100 nm,preferably 30 nm was formed by a plasma CVD method, and a polycrystalsilicon film was formed by irradiation of excimer laser light. As acrystallizing method of the amorphous silicon film, a thermalcrystallizing method called SPC, an RTA method using irradiation ofinfrared rays, a method of using thermal crystallization and laserannealing, or the like may be used.

Next, the polycrystal silicon film is patterned to form an island-likesemiconductor layer 402 having a source region, a drain region, and achannel formation region of the pixel TFT, and an island-likesemiconductor layer 403 having a source region, a drain region, and achannel formation region of the sensor TFT. Then a gate insulating film406 covering these semiconductor layers 402 and 403 is formed. The gateinsulating film 406 is formed to have a thickness of 100 nm by a plasmaCVD method using silane (SiH₄) and N₂O as a raw material gas (FIG. 5A).

Next, a conductive film is formed. Here, aluminum is used as aconductive film material. However, a film containing titanium or siliconas its main ingredient, or a laminate film of those may be used. In thisembodiment, an aluminum film with a thickness of 200 to 500 nm,typically 300 nm is formed by a sputtering method. For the purpose ofsuppressing occurrence of hillocks and whiskers, scandium (Sc), titanium(Ti), or yttrium (Y) of 0.04 to 1.0 wt % is made contained in thealuminum film.

Next, a resist mask is formed and the aluminum film is patterned to formelectrode patterns, so that a pixel TFT gate electrode 407 and a sensorTFT gate electrode 408 are formed.

Next, an offset structure is formed by a well known method. Further, anLDD structure may be formed by a well known method. In this way,impurity regions (source/drain regions) 409, 410, 412 and 413, andchannel regions 411 and 414 are formed (FIG. 5B). In FIGS. 5A to 5D, forconvenience of explanation, only the sensor TFT and the pixel TFT, whichare N-channel TFTs, are shown. However, P-channel TFTs are alsomanufactured. As an impurity element, P (phosphorus) or As (arsenic) maybe used for an N-channel type, and B (boron) or Ga (gallium) may be usedfor a P type.

Then a first interlayer insulating film 415 is formed, and contact holesreaching the impurity regions 409, 410, 412, and 413 are formed.Thereafter, a metal film is formed and patterning is made, so thatelectrodes 416 to 419 are formed. At this time, wiring lines forconnecting a plurality of TFTs are formed at the same time.

In this embodiment, the first interlayer insulating film 415 is formedof a silicon nitride film with a thickness of 500 nm. As the firstinterlayer insulating film 415, a silicon oxide film or a siliconnitride oxide film may be used other than the silicon nitride film. Amultilayer film of these insulating films may be used.

As the metal film as a starting film of the electrodes and wiring lines,in this embodiment, a laminate film composed of a titanium film, analuminum film, and a titanium film is formed by a sputtering method. Thethicknesses of these films are made 100 nm, 300 nm, and 100 nm,respectively.

Through the above process, the pixel TFT and the sensor TFT arecompleted at the same time (FIG. 5C).

Next, a metal film 420 being in contact with the first interlayerinsulating film 415 and the drain electrode 419 of the sensor TFT isformed. The metal film is grown and is patterned, so that a lowerelectrode 420 of a photoelectric conversion element is formed. In thisembodiment, although aluminum with a sputtering method is used for themetal film, other metals may be used. For example, a laminate filmcomposed of a titanium film, an aluminum film, and a titanium film maybe used.

Reference will be made to FIGS. 6A to 6C. Next, an amorphous siliconfilm (hereinafter referred to as a—Si:H film) containing hydrogen, whichfunctions as a photoelectric conversion layer, is formed on the entiresurface of the substrate, and patterning is carried out to form aphotoelectric conversion layer 421 (FIG. 6A).

Next, a transparent conductive film is formed on the entire surface ofthe substrate. In this embodiment, ITO with a thickness of 200 nm isformed as the transparent conductive film by a sputtering method. Thetransparent conductive film is patterned so that an upper electrode 422is formed (FIG. 6A).

Then a second interlayer insulating film 423 is formed. When a resinfilm of polyimide, polyamide, polyimide amide, acryl, or the like isformed as an insulating coat constituting the second interlayerinsulating film, a flat surface can be obtained, so that the resin filmis preferable. Alternatively, a laminated structure may be adopted suchthat the upper layer of the second interlayer insulating film is theforegoing resin film, and the lower layer is a single layer ormultilayer film of inorganic material such as silicon oxide, siliconnitride, or silicon nitride oxide. In this embodiment, a polyimide filmwith a thickness of 0.7 μm was formed as the insulation coat on theentire surface of the substrate (FIG. 6B).

Further, a contact hole reaching the drain electrode 416 is formed inthe second interlayer insulating film 423. Again, a transparentconductive film is formed on the entire surface of the substrate andpatterning is carried out, so that a pixel transparent electrode 424connected to the pixel TFT is formed.

Through the above steps, a component substrate as shown in FIG. 6C orFIG. 4 is completed.

The component substrate and an opposite substrate are bonded to eachother with a sealing material, and a liquid crystal is sealedtherebetween, so that the semiconductor device is completed. Thisopposite substrate is composed of a transparent substrate on which atransparent conductive film and an oriented film are formed. Other thanthese, a black mask or a color filter may be provided as the needarises.

(Embodiment 2)

In this embodiment, the pixel electrode in the embodiment 1 is made areflecting electrode made of a metal film, so that a semiconductordevice including a reflecting display portion is manufactured.

FIG. 7 is a sectional view of an active matrix substrate of asemiconductor device of this embodiment. Similarly to FIG. 4, FIG. 7shows a cross section of a pixel region A and a sensor portion B.Reference numeral 700 denotes a substrate, 701 denotes an underlayerfilm, 704 denotes a protective light shielding film of a pixel TFT, 705denotes a protective light shielding film of a sensor TFT, 706 denotes agate insulating film, 707 and 708 denote gate electrodes, 709, 710, 712,and 713 denote impurity regions (source/drain regions), 711 and 714denote channel regions, 715 denotes a first interlayer insulating film,716 to 719 denote electrodes (source/drain electrodes), 720, 721, and722 denote a lower electrode, a photoelectric conversion layer, an uppertransparent electrode of a photodiode, respectively, 723 denotes asecond interlayer insulation film, and 724 denotes a reflectingelectrode of the pixel TFT. Reference numerals 725 and 726 denotewindows (holes) provided in the reflecting electrode. Light of abacklight from the lower portion of the active matrix substrate passesthrough these windows toward the upper portion of the semiconductordevice. Reflected light from an object to be read passes through thewindow 726 and is incident on the photodiode. A transparent conductivefilm material or transparent resin film may be formed on the windows 725and 726.

Thus, in the case of the semiconductor device of this embodiment, aliquid crystal is driven in an ECB mode and is made normally black. Inthe case of this embodiment as well, in the case of a picture readingmode, the display is made white display. Even in the case where theliquid crystal is driven by another driving mode, in the case of thepicture reading mode, the display is made white display.

With respect to a manufacturing method of the semiconductor device ofthis embodiment, reference may be made to the embodiment 1.

As described above, the manufacturing process of the semiconductordevice of the present invention is the same as that of a conventionaldisplay device except the addition of the manufacturing step of aphotoelectric conversion element. Thus, since a conventionalmanufacturing process can be used, the semiconductor device can bemanufactured easily and at low cost. Moreover, in the semiconductordevice manufactured in the present invention, the shape and size of thesubstrate is not changed from a conventional panel even if the sensorfunction is incorporated. Thus, the device can be miniaturized and itsweight can be lessened.

Moreover, the light receiving area of the sensor cell is substantiallythe same as the pixel area of the display cell, and is larger ascompared with a single crystal CCD, so that the sensor of the presentinvention can be made highly sensitive. Moreover, electric powerconsumed by the image sensor of the semiconductor device of the presentinvention can be made lower as compared with a CCD structure.

What is claimed is:
 1. A semiconductor device comprising: a displayportion and an image sensor portion on a substrate, wherein a pluralityof cells are formed on the substrate in a matrix form, each of saidcells comprising a pixel portion having at least a pixel TFT and a pixelelectrode and a sensor portion having at least a sensor TFT and aphotoelectric conversion element; a pixel source driver circuit and apixel gate driver circuit connected to the pixel TFT and formed on thesubstrate; and a sensor horizontal driver circuit and a sensor verticaldriver circuit connected to the sensor TFT and formed on the substrate,wherein the photoelectric conversion element is located over the pixelUT and the sensor TFT, and under the pixel electrode, wherein said pixelelectrode comprises reflective material and has at least one windowtherein facing said photoelectric conversion element.
 2. A deviceaccording to claim 1, further comprising a backlight provided on a backsurface of the substrate.
 3. A device according to claim 1, wherein thesensor portion further has a reset TFT and a signal amplifying TFT onthe substrate.
 4. A device according to claim 1, wherein each of thepixel TFT and the sensor TFT comprises a crystalline semiconductor filmformed over the substrate as an active layer.
 5. A device according toclaim 1, wherein a lower electrode of the photoelectric conversionelement is connected to one of source and drain electrodes of the sensorTFT.
 6. A semiconductor device comprising: a display portion and animage sensor portion on a substrate, wherein a plurality of cells areformed on the substrate in a matrix form, each of said cells comprisinga pixel portion having at least a pixel TFT and a pixel electrode and asensor portion having at least a sensor TFT and a photoelectricconversion element; a pixel source driver circuit and a pixel gatedriver circuit connected to the pixel TFT and formed on the substrate;and a sensor horizontal driver circuit and a sensor vertical drivercircuit connected to the sensor TFT and formed on the substrate, whereinthe pixel electrode is reflective and has at least one window thereinfacing said photoelectric conversion element, wherein the photoelectricconversion element is located over the pixel TFT and the sensor TFT andunder the pixel electrode, and wherein the pixel TFT and the sensor TFTare formed on a same layer on the substrate.
 7. A device according toclaim 6, further comprising a backlight provided on a back surface ofthe substrate.
 8. A device according to claim 6, wherein the sensorportion further has a reset TFT and a signal amplifying TFT on thesubstrate.
 9. A device according to claim 6, wherein each of the pixelTFT and the sensor TFT comprises a crystalline semiconductor film formedover the substrate as an active layer.
 10. A device according to claim6, wherein a lower electrode of the photoelectric conversion element isconnected to one of source and drain electrodes of the sensor TFT.
 11. Asemiconductor device comprising: a display portion and an image sensorportion on a substrate, wherein a plurality of cells are formed on thesubstrate in a matrix form, each of said cells comprising a pixelportion having at least a pixel TFT and a pixel electrode and a sensorportion having at least a sensor TFT and a photoelectric conversionelement; a pixel source driver circuit and a pixel gate driver circuitconnected to the pixel TFT and formed on the substrate; and a sensorhorizontal driver circuit and a sensor vertical driver circuit connectedto the sensor TFT and formed on the substrate, wherein the pixelelectrode is reflective and has at least one window therein facing saidphotoelectric conversion element, wherein the pixel TFT and the sensorTFT are formed over light shielding films, respectively, and wherein thephotoelectric conversion element is formed over the pixel TFT and thesensor TFT and under the pixel electrode.
 12. A device according toclaim 11, further comprising a backlight provided on a back surface ofthe substrate.
 13. A device according to claim 11, wherein the sensorportion further has a reset TFT and a signal amplifying TFT on thesubstrate.
 14. A device according to claim 11, wherein each of the pixelTFT and the sensor TFT comprises a crystalline semiconductor film formedover the substrate as an active layer.
 15. A device according to claim11, wherein a lower electrode of the photoelectric conversion element isconnected to one of source and drain electrodes of the sensor TFT.
 16. Asemiconductor device comprising: a display portion and an image sensorportion on a substrate, wherein a plurality of cells are formed on thesubstrate in a matrix form, each of said cells comprising a pixelportion having at least a pixel TFT and a pixel electrode and a sensorportion having at least a sensor TFT and a photoelectric conversionelement, wherein a pixel driver circuit and a sensor driver circuit areon the same substrate, wherein the photoelectric conversion element isformed over the pixel TFT and the sensor TFT and under the pixelelectrode, and wherein said pixel electrode comprises reflectivematerial and has at least one window therein Pacing said photoelectricconversion element.
 17. A device according to claim 16, furthercomprising a backlight provided on a back surface of the substrate. 18.A device according to claim 16, wherein the sensor portion further has areset TFT and a signal amplifying TFT on the substrate.
 19. A deviceaccording to claim 16, wherein each of the pixel TFT and the sensor TFTcomprises a crystalline semiconductor film formed over the substrate asan active layer.
 20. A device according to claim 16, wherein a lowerelectrode of the photoelectric conversion element is connected to one ofsource and drain electrodes of the sensor TFT.